Effects of preloading with consolidation on undrained bearing capacity of skirted circular footings

This paper reports a set of centrifuge tests to investigate the increase in bearing capacity of a skirted circular foundation that results from preloading with consolidation. Results are compared with coupled numerical analyses using the modified Cam Clay model. Fundamental mechanisms are revealed from the stress paths followed during preloading and consolidation at the element level, accounting for both the change in mean normal effective stress and in the hardening parameter. A formulation is developed to predict the gain in bearing capacity as a function of the level of preloading applied on the foundation and the degree of consolidation achieved. The formulation provides good agreement with the centrifuge results.